The blame game preceding the mid-year economic statement is reaching nonsense proportions.

Tony Abbott is saying, with a straight face, that a budget document brought down 100 days after he won office, and incorporating all the policy decisions he has made, is in fact “Labor’s last budget statement”.

And he is also contending, similarly seriously, that it will be “the only truthful budget statement Labor has ever made”.

That’s a pretty big slight on the heads of Treasury and Finance, who signed off on the pre-election fiscal outlook, against which the blow-out in the budget deficit to be unveiled on Tuesday will be measured, and which is, by law, an entirely apolitical document designed to inform an election campaign with absolutely no political interference from the caretaker government of the day.

Cutting the spin and hyperbole, the budget deficit is bigger by at least $12bn over the four years of the forward estimates because of decisions the government has taken, by at least another $1.2bn because, according to the government, Labor left insufficient money in the budget to pay for policies both sides supported, by at least $15bn because of government-proposed spending cuts that Labor and the Greens have blocked and by an unknown amount because government revenue has, once again, declined.

In the first category is the decision to boost the Reserve bank's capital at a cost of $8.8bn, and tax cuts proposed by Labor but not proceeded with by the Coalition at a cost of $3.1bn, including the changes to fringe benefits tax on company cars and the tax that was to be imposed on super earnings over $100,000, and a decision to keep $1bn in roads funding even though the Coalition had said it would be scrapped because it was nominally funded from the mining tax which it wants to repeal.

In the second category is the government’s claimed $1.2bn shortfall in the cost of running offshore detention centres, and an as yet unspecified amount to pay for the public service redundancies already in process. The government has deferred its own planned redundancies and this will now be a cost to budget rather than the promised $5.2bn saving.

And in the third category are the university cuts which Labor proposed before the election but is now blocking, worth $2.3bn, and about $13bn the programs nominally paid for by the mining tax which the Coalition still does want to abolish but which Labor is blocking, including the low income earner superannuation contribution and the schoolkids bonus to low and middle income earners, which has been legislated and not yet repealed and, it would appear, the government will now have to pay.

A new government does inherit a whole lot of things it finds unpleasant and wishes were different, in the Coalition’s case a starting point of $30.1bn deficit for this year, which now appears set to blow out to closer to $50bn. It makes decisions and spends money. It gets understandably frustrated when the opposition parties combine in the Senate to block, at least for a time, savings it wants to make – think back to the Labor government and the means test on the private health insurance rebate or the alcopops tax.

A new prime minister might get justifiably grumpy at all of that, but, quite obviously, it does not mean his first economic statement is in its entirety the work of the other side.